Whenever there's a big fight in professional boxing the most sought-after opinion by writers and commentators are from those fighters who have either fought or sparred the participants who are going to fight.

Which makes total sense because who could possibly provide more insight as to what it's like being in front of a pair of hands you can't see like the pair Sugar Ray Leonard possessed, or what it feels like to be at the end of a missile disguised as Thomas Hearns' right hand? The who in this case went by the name of Randy Shields.

Prior to the Leonard-Hearns showdown back in September of 1981, Shields was the highest profile fighter who had fought both Leonard and Hearns. In October of 1978 Shields lost a 10 round unanimous decision to Leonard. Eighteen months later Shields challenged Hearns for the WBA welterweight title and lost when he wasn't allowed to come out for 13th round. In the run up to Leonard-Hearns, Shields was inundated with requests for him to compare and contrast the two fighters and ultimately pick the winner.

Most times fighters aren't completely honest when asked for their opinion of a particular fighter who they've fought because they often times have a subconscious agenda that influences what they think and say. However, Randy Shields came across without an agenda when he voiced his thoughts on Ray and Tommy, not to mention he was spot on with his prediction. He basically said Hearns was clearly the bigger puncher, but Leonard because of his speed and versatility was more dangerous and would figure a way to neutralize Hearns' reach and power and win the fight. Shields called the fight right but he's more the exception than the rule.

Last week former WBO junior welterweight champ Kendall Holt and former IBF junior welterweight champ Paulie Malignaggi both picked Miguel Cotto to defeat Manny Pacquiao when they fight next month. Both Holt and Malignaggi implied that Cotto will be too physically strong for Pacquiao to handle. And Holt used Cotto's performances against Zab Judah and Shane Mosley as proof that Miguel can handle the fastest fighters in the world. They also agreed that Pacquiao beat a dried out and ring worn version of Oscar De La Hoya when he fought him this past December.

Obviously Holt and Malignaggi are very informed observers. There's also merit in what they say about Pacquiao beating an eroded version of De La Hoya, which in all fairness wasn't the prevailing thought by everyone before the fight. And if it was a guarantee that the same Cotto who fought Judah and Mosley was going to show up on November 14th and fight Pacquiao, it would be hard to pick against him. But that's not reality. The reality is Cotto is not the same fighter now in late 2009 as he was in 2007. He's also much more prone to getting cut and busted up and doesn't fight with the confidence and belief that he can't lose.

Both Holt and Malignaggi have strongly endorsed Cotto which is a welcome change being that most fighters usually hedge when they're asked to pick the winner of a big fight. Although their opinion is highly valued, neither has ever fought Pacquiao. Most of the time fighters who actually fought both opponents in an upcoming fight don't agree on who will win for a plethora of reasons. Sometimes they'll favor the fighter they did better against or defeated, or they'll pick the one who they're better friends with or the one who by him winning enhances their own reputation, in hindsight. Fighters also occasionally choose politically. They may be thinking about how to best maximize their own chances for a payday against one of the guys somewhere down the line.

Fighters who fought a common opponent often view them much differently. Prior to the first Frazier-Ali fight, Jerry Quarry and Oscar Bonavena were Ali's two most recent opponents and both had recently fought Joe Frazier. When Quarry was asked who he thought would win after fighting Ali he didn't hesitate and said Joe was too tough and would probably stop him. Six weeks later Ali beat Bonavena. Immediately after the fight Howard Cosell couldn't resist and asked Oscar who he picked to win between Ali and Frazier. And like Quarry, Bonavena didn't hesitate and declared Ali was the superior fighter and wouldn't have any trouble beating Frazier.

Looking back it was easy to see why Quarry and Bonavena said what they did based on their fights with Muhammad and Joe. In Quarry's case he probably wasn't blown away by Ali the fighter because he lost due to a cut and didn't feel as though he was out-manned against him. On the other hand he went to war with Frazier and lost a toe-to-toe slug-fest and no doubt was more hurt by Joe than he was Ali. In regards to Bonavena, his short stature somewhat nullified Frazier's body attack which led to Oscar going the distance with Frazier twice, not to mention he had Frazier down twice in their first fight. Also, Frazier never really had Bonavena in trouble or close to going down or out. However, Ali hurt Bonavena badly in the last round of their bout and was the first and only fighter to ever stop him. Which no doubt left an impression on Oscar and made it easy for him to reason why Ali would beat Frazier.

I remember asking Evander Holyfield at the post fight press-conference after his fight with Hasim Rahman who he favored to win next week between Lennox Lewis and Mike Tyson. With Evander having shared shared the ring with both guys twice each, his insight was welcome. And just as Quarry and Bonavena didn't blink answering about Ali and Frazier, neither did Holyfield hesitate in picking between Lewis and Tyson.

He said, “Oh, I like Mike to beat Lennox, he's much tougher.” As we continued to speak it was so apparent that Evander respected Tyson much more as a fighter than he did Lennox. It was if he was coming from the same mindset as Quarry did comparing Ali and Frazier. Evander came across as if Lennox didn't beat him nor was he ever in fear of losing or being hurt by him, as opposed to him having to fight and literally take it from Tyson. It was almost as if Holyfield was dismissive towards Lewis and thought of Tyson as being the tougher and braver fighter.

And it's for reasons like the above that the common opponent evaluation is not the be all-end all when it comes to picking the winner of a fight. It's interesting to hear what a common opponent of both fighters has to say, but they get it wrong as much as they do right.